This is the first competing renewal of the Yale Research Training Program in Geriatric Clinical Epidemiology. The objective of the Yale Program is to develop a cadre of physician scientists and PhD investigators with expertise in geriatric clinical epidemiology who will be equipped to address the myriad of unanswered questions concerning the diagnosis, treatment, management, prevention, and prognosis of the health problems experienced by the ever increasing number of older persons. We will accomplish this objective by providing highly qualified physicians, who are already well trained in geriatrics and/or subspecialties with age-related relevance, and outstanding PhD-trained investigators with 2 to 3 years of rigorous research training. Our trainees will develop skills in each of seven essential areas: 1) formulation of significant and focused research questions and hypotheses;2) design of observational and experimental studies to address focused research questions;3) techniques for successful execution of specific study designs;4) critical analysis of the scientific literature, including research methods and data quality;5) interpretation of findings; 6) verbal and written communication of scientific methods and findings;and 7) development and implementation of strategies for research support. These skills will be developed through a training experience that includes both didactic and experiential components. The didactic curriculum includes a series of modules offered through the Robert Wood Johnson Clinical Scholars Program, key courses offered through the K30-sponsored Investigative Medicine Program, and advanced courses offered through the School of Public Health. The central component of the Yale Program is a mentored research experience, which includes structured meetings with Program Faculty in geriatrics/gerontology and a supervised research project tailored to the trainee's experiences and interests, with the goal of producing one or more first-authored, peer-reviewed publications and a grant application to support further research. Trainees have the option of obtaining an MPH or a PhD. During the initial funding cycle, the Yale Program has successfully recruited and retained a full complement of highly qualified MD and PhD trainees and has started to export its graduates to tenure-track, research-intensive positions at top-tier academic institutions. We request continued funding for five postdoctoral positions per year for the next five years.